Process for melting and casting ruthenium-containing or iridium-containing titanium alloys

ABSTRACT

An improved process for successful and homogeneous incorporation of ruthenium and iridium into titanium and titanium alloy melts, ingots, and castings via traditional melting processes (e.g., VAR and cold-hearth) has been developed. This result is achieved through the use of low-melting point Ti-Ru or Ti-Ir binary master alloys within the general composition range of ≦45 wt. % Ru and with a preferred composition of Ti-(15-40 wt. % Ru), or within the general composition range of ≦61 wt. % Ir and with a preferred composition of TI-(20-58 wt. % Ir). Primary features are its lower melting point than pure titanium, lower density than pure Ru and Ir metals, and the ability to be readily processed into granular or powder forms.

BACKGROUND OF THE INVENTION

[0001] 1. Technical Field

[0002] The present invention relates to processes for producing titaniumalloys and more particularly to processes for melting and castingruthenium and iridium containing titanium alloys.

[0003] 2. Background Information

[0004] Platinum-group metals have been incorporated into variouscommercial titanium alloys over the past forty years primarily for thepurpose of improving and expanding corrosion resistance. The mostprominent examples are the Ti-Pd binary alloys, ASTM Grades 7 and 1 1(Ti-0.15 wt. % Pd), and Grades 16 and 17 (Ti-0.05 wt. % Pd) which havebeen widely used in severe, corrosive service in the chemical processindustry. This minor 0.04-0.25 wt. % Pd addition to titanium and itsalloys dramatically enhances its resistance to dilute reducing acid(HCl, H₂SO₄) media, as well as to crevice corrosion in hot chloride orhalide salt solutions (brines).

[0005] The formulation, melting, and casting of these commercial Ti-Pdalloys is routinely and readily accomplished using the same standard,established methods/practices used for unalloyed titanium and mostcommon titanium alloy mill products and components. This includes directblending or addition of palladium metal powder to titanium metal spongeand/or revert, and subsequent melting via vacuum arc remelting (VAR),electron beam (EBM) melting, plasma arc melting (PAM), and VAR skullmelting (for shaped castings) methods. These classic methods haveproduced acceptable, very chemically homogeneous ingots and castingsstemming from palladium's slightly lower melting point than titanium(Table 1).

[0006] As the market price of palladium metal continued to rise, such asthe $140 to over $600 per Troy oz. increase in 1999, the price of Ti-Pdmill products became too exorbitant for most chemical processapplications, and dramatically thwarted its selection and use. In aneffort to provide lower cost substitutes for various expensive Ti-Pdalloys, various Ti-Ru binary alloys have been developed, such as ASTMGrades 26 and 27 (Ti-0.1 wt. % Ru). Such Ti-Ru alloys often exhibitcomparable corrosion resistance and mechanical/physical properties tothe Ti-Pd alloys. Since these alloys were formulated using rutheniummetal additions which are currently on the order of one-sixth the priceof palladium, these Ti-Ru alloys also offer substantial cost savingsover similar Ti-Pd mill products.

[0007] Over the past decade several commercial high-strengthruthenium-containing alpha-beta and beta titanium alloys have beendeveloped and qualified. These alloys include ASTM Grades 29(Ti-6Al-4V-0.1Ru), 28 (Ti-3Al-2.5V-0.1Ru), andTi-3Al-8V-6Cr-4Zr-4Mo-0.1Ru alloys, which are commercially utilized inhigh temperature, corrosive energy industry service, such as geothermalbrine production well casing, oil/gas production tubulars and offshoreriser components.

[0008] At the current price of $415.00/Troy oz., iridium metal is also amore cost effective alloy addition than Pd or Pt. Since iridium exhibitssimilar electrocatalytic behavior as Pt, the possibility exists that itcan be added to titanium alloys in amounts as low as 0.05 wt. %nominally to enhance corrosion performance.

[0009] Although ruthenium (Ru) and iridium (Ir) are desirable, lowercost means of upgrading titanium alloy resistance than palladium (Pd),traditional methodologies for formulation and melting of Ru andIr-containing titanium alloys based on direct elemental Ru or Ir metaladditions to titanium melts pose distinct concerns and difficulties forachieving alloy compositional homogeneity. Specifically, ruthenium andiridium metals represent a “refractory”, difficult-to-melt-in additionsto titanium using traditional melting processes such as VAR and EBM/PAMhearth processes. Attempts to utilize accepted methods of directaddition of elemental powder employed successfully with Pd metaladditions over the years, has been known to result in Rumacrosegregation and serious inhomogeneities with respect to Ru contentin Ti-0.1Ru alloy ingots and castings. Although this gross inhomogeneityin Ru or Ir can be minimized in ingots/castings by direct Ru or Iraddition to individual Ti compacts, use of fine Ru or Ir powders, and/orimproved blending with sponge granules, it is difficult to avoid. Infact, this problem is aggravated and enhanced when producing Ru- orIr-containing Ti alloy heats via EBM or PAM hearth processes.

[0010] This difficulty in achieving homogeneous titanium melts usingruthenium metal additions primarily stems from ruthenium's and iridium'sexceptionally high melting point and density, which are roughly 675° C.(1215° F.) and 781° C. (1406° F.) above that of pure titanium metal,respectively (see Table 1). In contrast Pd metal melts 110° C. (198° F.)below that of titanium. Furthermore, Ru and Ir metals both possess asubstantially higher latent heat of fusion compared to either Ti or Pdmetal (Table 1), which further inhibits their ability to transition fromsolid particle to liquid form (melt). On the other hand, Ru and Ir havea comparable specific heat but much higher thermal conductivity than Pd,which can be expected to partially counteract these refractory Ru and Irproperties which retard melt kinetics.

[0011] Two key factors for successful melting of any alloy addition intoa titanium alloy melt are: 1) achieving sufficient temperature to exceedthe melting point of the addition, and 2) allowing sufficient residencetime of the particle addition within the high energy source and thesuperheated Ti melt to fully melt/dissolve the added particles. In thecase of VAR melting of titanium from consumable electrodes, thepre-heated electrode compact adjacent to the electric arc becomes veryhot and can pre-sinter compacted Ru and/or Ir metal powders into moredifficult-to-melt, larger, consolidated clumps exhibiting lowsurface-to-volume ratio and a larger thermal mass. Pre-blending Ticompacts using very fine Ru or Ir powder helps, but classification andsettling of the fine Ru or Ir powder mixed with coarse Ti metal spongeand other master alloy granules is inevitable and unavoidable prior tocompacting. Although high temperatures well above ruthenium's andiridium's melting point are achieved within the electric arc, residencetime is very short and actual Ru or Ir particle size mass can be toolarge to ensure total melting of refractory Ru or Ir additions. Withruthenium's and iridium's much higher density (Table 1) compared to Ti,these heavy unmelted Ru and Ir particles tend to settle rapidly withinthe liquid Ti melt causing macrosegregation and gross chemicalinhomogeneity in ingots and castings.

[0012] Although Ru or Ir powder pre-sintering within electrode compactsis not a relevant concern in cold-hearth melt processes, the concern forincomplete Ru and/or Ir particle melting is even greater in these typesof processes. This concern stems from:

[0013] 1) The minimal, extremely short exposure of the solid Ti/Ru orTi/Ir metal input mixture to either the electron beam or plasma arc asthey raster across the metal and/or liquid melt surface.

[0014] 2) The relatively low superheat in the titanium melt pool,involving temperatures well below ruthenium's or iridium's high meltingpoint, and

[0015] 3) The high density of unmelted Ru and Ir metal particles whichpromotes rapid settling (gross macro-segregation) of Ru and Ir particleswithin the very shallow Ti melt pool as it flows over the cold hearth.

SUMMARY OF THE INVENTION

[0016] It is an object of the present invention to provide an effectivemeans for using Ru and Ir as a cost means of upgrading titanium alloycorrosion performance to achieve the required reducing acid, crevice,and stress corrosion.

[0017] The present invention is an improved process for successful andhomogeneous incorporation of ruthenium into titanium and titanium alloymelts, ingots, and castings via traditional and contemporary meltingprocesses (e.g., VAR and cold-hearth) has been developed. This isachieved through the use of low-melting point Ti-Ru binary master alloywithin the general composition range of ≦45 wt. % Ru, and with apreferred composition of >15 wt. % and ≦40 wt. % Ru. For iridium a lowmelting point Ti-Ir binary master alloy containing <61 wt. % Ir, with apreferred range of >20 and ≦58 wt. % Ir. Desirable features as a masteralloy for titanium melt processes are outlined in Table 4. Primaryfeatures are their lower melting point than pure titanium, lower densitythan pure Ru and Ir, and the ability to be readily processed intogranular or powder forms.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The preferred embodiment of the invention, illustrative of thebest mode in which applicant contemplated applying the principles, isset forth in the following description and is shown in the drawings andis particularly and distinctly pointed out and set forth in the appendedclaims.

[0019]FIG. 1 is a titanium-ruthenium binary alloy phase diagramapplicable to a preferred embodiment of the master alloy of the presentinvention;

[0020]FIG. 2 is a titanium-iridium binary alloy phase diagram applicableto an alternate preferred embodiment of the master alloy of the presentinvention;

[0021]FIG. 3 is a graph showing a room temperature fracture toughness ofvarious Ti-Ru master alloy compositions of the present invention; and

[0022]FIG. 4 is a schematic illustration of a cold-hearth ingot madeaccording to the process of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] Ruthenium or iridium can be readily, homogeneously, andsuccessfully incorporated into titanium and titanium alloy melts,ingots, and castings via traditional melting processes through the useof low-melting Ti-Ru or Ti-Ir binary master alloys within a specificcomposition range. These master alloys possesses a lower melting pointand density than pure titanium and ruthenium/iridium, respectively, andare friable and can be easily granulated for formulation and blendingwith Ti sponge, etc., to produce compacts or direct granular feed forVAR, cold-hearth, and casting melt processes. Although the relevantTi-Ru master alloy composition in this invention generally falls in the0.5-45 wt. % Ru range, the preferred composition as a master alloy liesabove 15 wt. % and less than or equal to 40 wt. %. For the Ti-Ir masteralloy, the relevant composition claimed generally falls in the 0.5-61wt. % to range with a preferred composition above 20 wt. % and less thanor equal to 58 wt. % iridium.

[0024] Metallurgical Considerations—Ruthenium-rich binary Ti-Ru alloysare characterized by elevated melting points and difficult-to-melt,brittle phases. As shown in the published binary phase diagram fortitanium-ruthenium in FIG. 1, ruthenium content above approximately42-45 wt. % produces melting points well above those of pure titanium,approaching that of pure ruthenium [2237° C. (4239° F.)]. Furthermore,due to the significant difference in atomic radii between Ti and Ru,this Ru-rich regime involves formation of the very brittle intermetalliccompound TiRu (Ti-67.5 wt. % Ru). This compound exhibits an elevatedmelting point of 2130° C. (3866° F.) which is also very difficult tomelt via conventional VAR/Hearth melt processes. These Ru-richcompound-containing as-cast master alloy heats also did not remainmonolithic and tended to experience severe, extensive cracking uponsolidification and cooling (Table 2).

[0025] Although a lower melting eutectic composition occurs at 86 wt. %Ru (FIG. 1) which exhibits reasonable melt fluidity and did not crack-upafter solidification/cooling, its melting point is roughly 1825° C.(3317° F.). This is still 163° C. (294° F.) above titanium's meltingpoint and typical liquid melt temperatures.

[0026] Although their brittle nature may be of benefit for processinginto master alloy granules or powders, these Ru-rich Ti-Ru master alloycompositions still possess high melting points, high density, and highheat of fusion compared to titanium. From a Ti alloy formulationstandpoint, their high Ru contents can translate into greaterinaccuracies in final ingot/casting Ru content due to greater analyticalerror and handling/processing losses prior to compacting or melting.

[0027] Iridium-rich binary Ti-Ir alloys are also characterized byelevated melting points and difficult-to-melt brittle phases. Asindicated by the published binary phase diagram for titanium-iridium asdepicted in FIG. 2, alloy melting points well above those of puretitanium can be expected when Ir content exceeds approximately 58-61 wt.%. Due to an even greater discrepancy in atomic radii between Ti and Ir,the Ir-rich side of the phase diagram tends to form brittleintermetallic compounds [Ti₃Ir (26 wt. % Ir), TiIr (76 wt. % Ir), andTiIr₃ (92 wt. % Ir). Of these, the leaner Ti₃Ir compound exhibits amelting point which is near that of titanium (˜1670° C.). The other twocompounds exhibit undesirable, elevated melting temperatures exceeding˜2000° C. These latter two compounds represent extremelydifficult-to-melt master alloy additions via conventional VAR/hearthmelt processes. Although these Ir-rich alloy compositions are brittleand friable for processing into master alloy granules/powders, theystill possess an elevated melting point, high density, and a high heatof fusion compared to titanium.

[0028] a. Preferred Ti-Ru Master Alloy Composition—The Ru-lean Ti-Rucompositions (≦42 wt. % Ru), on the other hand, represent highlyattractive master alloy additions to titanium and titanium alloys. Asindicated in FIG. 1, the Ru-lean regime consists primarily of beta phasetitanium and no intermetallic compounds, possessing melting pointtemperatures below that of pure titanium. These compositions tend toexhibit rapid melting and good melt fluidity, and less tendency to“crack-up” severely after solidification/cooling (Table 2) due tointernal residual stresses and absence of TiRu compound phase.

[0029] In addition to melting points below that of titanium, theselean-Ru master alloys possess physical properties approaching those oftitanium such as lower latent heat of fusion and lower density.Furthermore, this low-to-intermediate Ru content in the master alloyaddition translates into greater analytical accuracies with respect toRu content and reduced error in Ti alloy formulation where the effect ofmaster alloy losses during handling/processing prior tocompacting/melting is mitigated.

[0030] Since this master alloy addition is desirable in granular orpowder form, the preferred Ti-Ru composition range is further defined tobe in the range from +20 wt. % to 58 wt. % Ir. This encompasses thecompositions where the Ti-Ru master alloy exhibits a melting point belowthat of pure titanium and relatively good friability (brittle behavior)for easy, low-cost mechanical processing, (e.g. crushing) into granularform. The very low fracture toughness properties of as-cast Ti-Ru masteralloys at room temperature are evident from FIG. 2 data plots. At andbelow roughly 15% Ru, the more ductile master alloy is much moredifficult to granularize using standard impact and/or crushing methodsunder ambient conditions.

[0031] b. Preferred Ti-Ir Master Alloy Composition—Ti-Ir compositionsinvolving Ir levels below approximately 61 wt. % offer desirableproperties as master alloy additions to titanium. This represents therange where the Ti-Ir master alloy's melting point is less than or equalto that of pure titanium. These compositions tend to exhibit rapidmelting and good melt fluidity (Table 3). The leaner-Ir side of thisrange tends to offer master alloy properties which better approach thoseof titanium, such as lower latent heat of fusion and density.

[0032] Since this master alloy addition is desirable in granular orpowder form, the preferred Ti-Ir composition range is further defined tobe in the range of from >20 wt. % to 58 wt. % Ir. This encompassescompositions where the Ti-Ir master alloy exhibits a melting point wallbelow that of titanium and relatively good friability (Table 3) foreasy, low-cost mechanical processing into granular form. Below roughly20-25% Ir, the more ductile master alloy becomes much more difficult togranulize (crush) under ambient conditions.

[0033] The process and compositions of this invention is furtherdisclosed with reference to the following examples.

EXAMPLE 1 Demonstration of Ti-Ru Master Alloy Use

[0034] This example demonstrates how a Ti-Ru master alloy described inthis invention was used to produce a chemically homogeneous ingot ofASTM Grade 26 titanium (Ti-0.11% Ru). Specifically, this methodology wasapplied to formulation and melting of a 90 lb. (41 kg) plasma-hearth(PAM) ingot of Ti-0.1 Ru utilizing a wide range of Ti-Ru master alloygranule sizes.

[0035] A Ti-30 wt. % Ru master alloy was selected and produced for thisexample. A 250 gram button heat of this master alloy was prepared byplasma melting a pre-blended compact of titanium sponge granules andruthenium metal powder. This button compact was melted in a Retechplasma button furnace using a plasma torch operating at 20 kW. Thecompact melted readily and exhibited high fluidity, and produced amonolithic button as expected. Chemical analysis confirmed that thewhole button was homogeneous at 30±1 wt. % Ru. The melting point of thismaster alloy was estimated to be 1620° C. (2947° F.), based on meltingpoints measured on the Ti-20% Ru and Ti-40% Ru master alloy buttons viaprecision extensometry under vacuum (1632° C. and 1606° C.,respectively).

[0036] After crushing up this brittle master alloy button in a mortarand pestle, four size fractions of granules were screened: −40, 1-6/+40,−4/+6, and +4. Each of these four master alloy fractions was used toformulate compacts for separate zones within the final ingot as shown inFIG. 4. These master alloy granules were all well blended withcommercial magnesium-reduced titanium sponge granules and pressed into1200 gram compacts.

[0037] These compacts were melted in a Retech plasma hearth meltingfurnace using two plasma torches (150 kW hearth and crucible torches)each operating at 96 kW (FIG. 4). The final 12.7 cm (5″) diameter, 41 kgingot was sectioned axially through its mid-section to extract a 19 mmthick cross-sectional slice for evaluation of chemical andmicrostructural homogeneity. At least six locations per zone (FIG. 4)were analyzed with respect to ruthenium content. Based on a total ofthirty analysis, the ruthenium content averaged 0.112 wt. % (0.120%max., 0.106% min.), with a very low standard deviation of 0.003 wt. %.

[0038] Therefore, not only was the nominal aim of 0.11% Ru met, the lackof significant deviation/scatter in Ru content indicated excellent ingothomogeneity/uniformity with respect to ruthenium. Microstructuralexamination of at least six mounted/polished/etched samples taken fromthis slice also consistently revealed a very fine, uniform dispersion ofruthenium-stabilized beta phase through the alpha-phase matrix.Extensive chemical analysis and microstructural examination of all fourzones of this PAM ingot indicate that all ruthenium was thoroughlymelted into and distributed homogeneously through this heat. Thisexample confirms the viability of Ti-Ru master alloy utilization, evenwhen using larger size fraction Ti-Ru master alloy granules for titaniumalloy formulation.

EXAMPLE 2 Characterization of Ti-Ir Master Alloy Compositions

[0039] Three Ti-Ir master alloy compositions, Ti-10 wt. % Ir, Ti-20 wt.% Ir, and Ti-40 wt. % Ir, were produced and evaluated in the laboratory.These compositions were produced as 250 gram button heats in a Retechplasma button furnace. Compacts produced by blending pure Ir metalpowder with titanium sponge granules were melted with plasma torchoperating at 20 kW under an argon gas atmosphere.

[0040] Both buttons melted readily and exhibited excellent meltfluidity. The Ti-10% Ir and -20% Ir buttons remained monolithic, whereasthe Ti-40% Ir button exhibited one single fracture upon solidification.Chemical analysis of these button heats revealed an iridium content of9.0, 19.8 and 39.2 wt. %, respectively, and good overall chemicalhomogeneity. Melting points of these buttons were determined viaprecision extensometry under vacuum, and found to average 1680° C., 1630and 1510° C., respectively. The Ti-10 Ir and -20 Ir buttons resistedfracture from hammer impact, whereas the Ti-40% Ir button readilyshattered upon impact and/or light crushing. The ready friability ofthis Ti-40% Ir composition at room temperature explains why thiscomposition lies in the “preferred” master alloy composition range.

[0041] 250 gram button heats of Ti-0.05% Ir and Ti-0.1% Ir weresubsequently produced in this plasma button furnace using the crushedTi-40% Ir button as master alloy. These Ti-40% Ir granules were blendedand compacted together with commercial magnesium-reduced titaniumsponge. Chemical analysis of these button heats confirmed that thedesired Ir content and homogeneity were achieved.

[0042] Accordingly, the improved PROCESS FOR MELTING AND CASTINGRUTHENIUM-CONTAINING OR IRIDIUM-CONTAINING TITANIUM ALLOYS issimplified, provides an effective, safe, inexpensive, and efficientdevice which achieves all the enumerated objectives, provides foreliminating difficulties encountered with prior devices, and solvesproblems and obtains new results in the art.

[0043] In the foregoing description, certain terms have been used forbrevity, clearness, and understanding; but no unnecessary limitationsare to be implied therefrom beyond the requirement of the prior art,because such terms are used for descriptive purposes and are intended tobe broadly construed.

[0044] Moreover, the description and illustration of the invention is byway of example, and the scope of the invention is not limited to theexact details shown or described.

[0045] Having now described the features, discoveries, and principles ofthe invention, the manner in which the PROCESS FOR MELTING AND CASTINGRUTHENIUM-CONTAINING OR IRIDIUM-CONTAINING TITANIUM ALLOYS is practiced,constructed and used, the characteristics of the practice andconstruction, and the advantageous new and useful results obtained; thenew and useful structures, devices, elements, arrangements, parts, andcombinations are set forth in the appended claims. TABLE 1 Comparison ofPure Metal Physical Properties Relevant to Melt Processes Pure MetalProperty Ti Pd Ru Ir Melting Point 1662° C. (3024° F.) 1552° C. (2826°F.) 2337° C. (4239° F.) 2443° C. (4430° F.) Heat of Fusion  15.5 KJ/mole 17.6 KJ/mole  24.0 KJ/mole  26.1 KJ/mole Specific Heat  0.52 KJ/kg. · °C.  0.24 KJ/kg · ° C.  0.24 KJ/kg · ° C.  0.13 KJ/kg · ° C. ThermalConductivity  22 W/m · ° C.  72 W/m · ° C.  117 W/m · ° C.  147 W/m · °C. Density   4.5 g/cm³  12.0 g/cm³  12.4 g/cm³  22.5 g/cm³

[0046] TABLE 2 Properties of Various Ti-Ru Master Alloy CompositionsConsidered Approx. Wt. % Melting Pt. Gross Impact As-Cast Button RuPhases Present ° C. (° F.) Toughness* Condition 10 β Ti + α Ti 1623(2950) fracture resistant no cracking 15 β Ti + minor α Ti 1602 (2913)fracture resistant no cracking 20 β Ti 1587 (2890) brittle no cracking30 β Ti 1550 (2822) very brittle/shattered no cracking 40 β Ti + TiRucmpd. (peritectic) 1575 (2867) very brittle/shattered heavily fractured50 β Ti + TiRu cmpd. 1840 (3344) very brittle/shattered heavilyfractured   67.5 TiRu compd. 2130 (3866) very brittle/shattered heavilyfractured 86 TiRu cmpd. + Ru (eutectic) 1825 (3317) brittle no cracking

[0047] TABLE 3 PROPERTIES OF TI-IR MASTER ALLOY COMPOSITIONS CONSIDEREDApprox. Gross Melting Impact As-Cast Wt. % Pt. Toughness Button IrPhases Present ° C. (° F.) * Condition 10 β Ti + α Ti + 1680 Fracture Nocracking Ti₃Ir cmpd. (3056) resistant 20 β Ti + Ti + 1630 Fracture Nocracking Ti₃Ir cmpd. (2966) resistant 40 β Ti + Ti₃Ir cmpd. 1510 VeryCracking (2750) brittle/ shattered 84 β Ti + TiIr₃ cmpd. 2000 BrittleCould not melt/ (3632) consolidate

[0048] TABLE 4 UNIQUE, DESIRABLE FEATURES OF THE PROPOSED TI-RU ANDTI-IR MASTER ALLOYS Lower melting point than pure titanium Dissolvesreadily into titanium and titanium alloy melts Significantly lowerdensity than Ru and Ir metals Easily and inexpensively processed intogranular or powder forms Possesses a desirable combination of lowerspecific heat and higher thermal conductivity than pure titanium forenhanced meltability into titanium Easy to melt master alloycompositions, which remain consolidated in as-cast form

What is claimed is:
 1. A process for manufacturing an alloy comprisingtitanium and a second metal selected from the group consisting ofruthenium and iridium, said process comprising the steps of: (a)producing a master alloy comprising titanium and said second metal,wherein said master alloy, titanium and said second metal each have amelting point, and said master alloy melting point is about equal to orlower than said titanium melting point, and said master alloy meltingpoint is lower than said second metal melting point; and (b) reducingsaid master alloy produced in step (a) in size and then blending saidreduced master alloy with a source of titanium.
 2. The process of claim1 wherein the master alloy formed in step (a) and said second metal eachhas a density and said master alloy density is less than said secondmetal density.
 3. The process of claim 1 wherein the master alloyproduced in step (a) is granulated in step (b).
 4. The process of claim3 wherein in step (b) the master alloy produced in step (a) is heatedafter said master alloy is reduced in size.
 5. The process of claim 1wherein in step (b) the source of titanium with which the master alloyproduced in step (a) is mixed is titanium sponge.
 6. The process ofclaim 4 wherein in step (b) the master alloy and source of titanium aremelted.
 7. The process of claim 4 wherein in step (b) the master alloyand source of titanium are cast.
 8. The process of claim 1 wherein instep (b) the blended master alloy and the source of titanium aresubjected to a vacuum-arc remelting (VAR) process.
 9. The process ofclaim 6 wherein in step (b) the blended master alloy and the source oftitanium are subjected to a cold-hearth, electron beam, or plasma arcmelting.
 10. The process of claim 1 wherein the master alloy meltingpoint is substantially less than the second metal melting point.
 11. Theprocess of claim 1 wherein the master alloy is a binary alloy.
 12. Theprocess of claim 1 wherein the second metal is ruthenium.
 13. Theprocess of claim 12 wherein in step (a) the master alloy containsruthenium in the amount of from about 0.5% to about 45% by weight. 14.The process of claim 13 wherein in step (a) the master alloy containsruthenium in the amount of from above 15% to about 40% by weight. 15.The process of claim 14 wherein the master alloy is a binary alloy. 16.The process of claim 1 wherein the second metal is iridium.
 17. Theprocess of claim 16 wherein in step (a) the master alloy containsiridium in the amount of from about 0.5% to about 61% by weight.
 18. Theprocess of claim 17 wherein in step (a) the master alloy containsiridium in the amount of from above 20% to about 58% by weight.
 19. Theprocess of claim 18 wherein the master alloy is a binary alloy.
 20. Aproduct of the process for manufacturing an alloy comprising titaniumand a second metal selected from the group consisting of ruthenium andiridium said process comprising the steps of: (a) producing a masteralloy comprising titanium and said second metal, wherein said masteralloy, titanium, and said second meal each have a melting point, andsaid master alloy melting point is about equal to or lower than eithersaid titanium melting point, and said master alloy melting point islower than said second metal melting point; and (b) reducing said masteralloy produced in step (a) in size and then blending said reduced masteralloy with a source of titanium.
 21. The product of the process of claim20 wherein the master alloy formed in step (a) has a density and saidsecond metal has a density and said master alloy density is less thansaid second metal density.
 22. The product of the process of claim 20wherein the master alloy produced in step (a) is granulated in step (b).23. The product of the process of claim 22 wherein in step (b) themaster alloy produced in step (a) is heated after said master alloy isreduced in size.
 24. The product of the process of claim 20 wherein instep (b) the source of titanium with which the master alloy produced instep (a) is mixed is titanium sponge.
 25. The product of the process ofclaim 24 wherein in step (b) the master alloy and source of titanium aremelted.
 26. The product of the process of claim 24 wherein in step (b)the melted master alloy and source of titanium are cast.
 27. The productof the process of claim 22 wherein in step (b) the blended master alloyand the source of titanium are subjected to a vacuum-arc remelting (VAR)process.
 28. The product of the process of claim 20 wherein in step (b)the blended master alloy and the source of titanium are subjected tocold-hearth electron beam, or plasma arc melting process.
 29. Theproduct of the process of claim 20 wherein the master alloy meltingpoint is substantially less than the second metal melting point.
 30. Theproduct of the process of claim 20 wherein the master alloy is a binaryalloy.
 31. The product of the process of claim 20 wherein the secondmetal is ruthenium.
 32. The product of the process of claim 30 whereinin step (a) the master alloy contains ruthenium in the amount of fromabout 0.5% to about 45% by weight.
 33. The product of the process ofclaim 32 wherein in step (a) the master alloy contains ruthenium in theamount of from above 15% to about 40% by weight.
 34. The product of theprocess of claim 33 wherein the master alloy is a binary alloy.
 35. Theproduct of the process of claim 20 wherein the second metal is iridium.36. The product of the process of claim 35 wherein in step (a) themaster alloy contains iridium in the amount of from about 0.5% to about61 % by weight.
 37. The product of the process of claim 36 wherein instep (a) the master alloy contains iridium in the amount of from above20% to about 58% by weight.
 38. The product of the process of claim 37wherein the master alloy is a binary alloy.
 39. A titanium-rutheniumalloy comprising ruthenium in an amount of from about 0.5% to about 45%by weight and titanium in an amount of from about 55% to about 99.5% byweight.
 40. The titanium-ruthenium alloy of claim 39 which comprisesruthenium in the amount of from above 15% to about 40% by weight. 41.The titanium-ruthenium alloy of claim 40 which is a binary alloy. 42.The titanium-ruthenium alloy of claim 39 which has a melting temperatureequal to or less than about 1670° C.
 43. The titanium-ruthenium alloy ofclaim 42 which has a density of less than about 12.2 g/cm³.
 44. Atitanium-iridium alloy comprising titanium in the amount of from about0.5% to about 61% by weight and titanium in the amount of about 39% toabout 99.5% by weight.
 45. The titanium-iridium alloy of claim 44 whichcomprises iridium in the amount of from above 20% to about 58% byweight.
 46. The titanium-iridium alloy of claim 45 which is a binaryalloy.
 47. The titanium-iridium alloy of claim 44 which has a meltingtemperature equal to or less than about 1670° C.
 48. Thetitanium-iridium alloy of claim 47 which has a density of less thanabout 22.42 g/cm³.
 49. A titanium-ruthenium binary master alloyconsisting essentially of ruthenium in an amount of from about 0.5% toabout 45% by weight and titanium in an amount of from about 55% to about99.5% by weight.
 50. The titanium-ruthenium binary master alloy of claim49 which comprises ruthenium in the amount of from about 15% to about40% by weight.
 51. The titanium-ruthenium alloy of claim 50 which has amelting temperature equal to or less than about 1670° C.
 52. Thetitanium-ruthenium alloy of claim 51 which has a density of less thanabout 12.2 g/cm³.
 53. A titanium-iridium binary master alloy consistingessentially of ruthenium in an amount of from about 0.5% to about 61% byweight and titanium in an amount of from about 39% to about 99.5% byweight.
 54. The titanium-iridium binary master alloy of claim 53 whichcomprises ruthenium in the amount of from about 20% to about 58% byweight.
 55. The titanium-iridium alloy of claim 54 which has a meltingtemperature equal to or less than about 1670° C.
 56. Thetitanium-iridium alloy of claim 55 which has a density of less thanabout 22.42 g/cm³.